My invention comprises improvements in electromagnetic clutch and pulley assemblies for a refrigerant gas compressor adapted especially for use with an air conditioning system for automotive vehicles wherein the compressor is drivably connected to the vehicle engine crankshaft with a pulley drive. In an arrangement of this kind, it is common practice to mount a driven pulley on a stationary nose or sleeve journal support that forms a part of the housing or that is connected with threaded fasteners to the housing. A driveshaft for the compressor rotor in such conventional arrangements is journalled within the journal support.
An electromagnetic clutch for controlling torque distribution from the driven pulley to the rotor includes a fixed coil winding and a core that establishes an electromagnetic flux flow path through a clutch friction member. A clutch engagement plate is disposed adjacent the friction member and is connected to the driveshaft for the rotor. A typical arrangement of this kind is shown in U.S. Pat. No. 4,718,526.
Another prior art clutch and pulley bearing arrangement is shown in U.S. Pat. No. 3,415,347. This includes a driven pulley for the compressor shaft that is journalled on the driveshaft. The rotor in turn is journalled within the stationary nose or extension of the fixed housing for the compressor. An electromagnetic clutch friction member is connected to and supported by the driveshaft. A clutch engagement plate is resiliently connected to the pulley, unlike the arrangement in U.S. Pat. No. 4,718,526 where the engagement plate for the electromagnetic clutch is connected drivably to the rotor of the compressor.
In prior art constructions such as those described in the '347 and in the '526 patents, the clutch engagement plate, upon actuation of the electromagnetic clutch, engages the friction plate of the electromagnetic clutch and causes an undesirable noise that is audible in the passenger compartment of the vehicle. There is no acoustic barrier for the clutch components in the engine compartment of the vehicle.